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PSStable Isotope Profiles in an Isolated Carbonate Platform: Implications for Stratigraphic Correlations*
Jean Hsieh1, David Katz1, Paul (Mitch) Harris1, Matt Buoniconti1, John Humphrey2, and Isabel Montanez3
Search and Discovery Article #50132 (2008)
Posted November 12, 2008
*Adapted from oral presentation at AAPG International Conference and Exhibition, Cape Town, South Africa, October 26-29, 2008.
1 Chevron ETC - San Ramon, CA([email protected],[email protected], [email protected])
2 Colorado School of Mines, Department of Geology, Golden, CO
3 UC - Davis, Department of Geology, Davis, CA
The δ13Ccarb values of biotically and abiotically precipitated marine carbonates display significant temporal variation that is well
documented through the geological record (e.g., Popp et al., 1997). These variations have been attributed to changes in carbon cycling through changes in productivity and organic carbon burial rates, variations in carbon sources to the atmosphere and ocean, and shifts in weathering patterns and rates. The potential of secular variation in marine carbonate δ13Ccarb records as a chronostratigraphic correlation tool and paleoenvironmental proxy has been
well
established over the past two decades (e.g., Vahrenkamp, 1996; Montanez et al, 2000; Saltzman, 2002). However, carbonates are susceptible to diagenetic modification, particularly those deposited in shallow-water epeiric seas subjected to sea-level fluctuations. Thus, potential diagenetic influences on the δ13Ccarb values must be considered when interpreting measured values.
This study presents the results of measurements of the carbon and oxygen isotopic values from the late Visean through the Bashkirian for an isolated carbonate platform. We are examining the implications of the bulk rock stable isotope profiles for stratigraphic correlation in a reservoir. The δ13C stratigraphy shows trends to positive and negative δ13C values that can be correlated with sequence
boundaries picked, using traditional facies variations based on core descriptions. Secular variability in the δ13C stratigraphy is also loosely correlated with changes in wireline
log
values. Several
sequence
boundaries could be modified and higher order cycle boundaries could be picked using the δ13C stratigraphy. These results suggest that stable isotope profiles can be used to help constrain the
sequence
stratigraphic framework of a carbonate reservoir.
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Isotopic Profiles and Their Use
Thanks to Jeroen Kenter, Ted Playton, and James Bishop for informative discussions. Bruckschen, P., S. Oesmann, and J. Veizer, 1999, Isotope stratigraphy of the European carboniferous; proxy signals for ocean chemistry, climate and tectonics: Chemical Geology, v. 161/1, p. 127-163. Denison, R.E., R.B. Koepnick, W.H. Burke, E.A. Hetherington, and A. Fletcher, 1994, Construction of the Mississippian, Pennsylvanian and Permian seawater87Sr/86Sr curve: Chemical Geology, v. 112/1-2, p. 145-167. Fielding, C.R., J. Whittaker, S.A. Henrys, T.J. Wilson, and T.R. Naish, 2008, Seismic facies and stratigraphy of the Cenozoic succession in McMurdo Sound, Antarctica; implications for tectonic, climatic and glacial history: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 260/1-2, p. 8-29. Grossman, E.L., T.E. Yancey, T.E. Jones, P. Bruckschen, B. Chuvashov, S.J. Mazzullo and H. Mii, 2008, Glaciation, aridification, and carbon sequestration in the permo-carboniferous: the isotopic record from low latitudes: Palaeographhy, Palaeoclimatology, Palaeoecology, v. 268/3-4, p. 222-233. Isbell, J.L., P.A. Lenaker, R.A. Askin, M.F. Miller, and L.E. Babcock, 2003, Reevaluation of the timing and extent of late Paleozoic glaciation in Gondwana; role of the transantarctic mountains: Geology, v. 31/11, p 997-980. Katz, M.E., K.G. Miller, J.D. Wright, B.S. Wade, J.V. Browning, B.S. Cramer, and Y. Rosenthal, 2008, Stepwise transition from the Eocene greenhouse to the Oligocene icehouse: Nature Geoscience, v. 1, p. 329-334. Kenter, J.A.M., and, P.M. Harris, 2006, Web-based outcrop digital analog database (WODAD); archiving and searching carbonate platform margins: AAPG Annual Convention, Houston, Texas, 9-12 April, 2006, AAPG Search and Discovery article #40300, web http://www.searchanddiscovery.net Korte, C., T. Jasper, H.W. Kozur, and J. Veizer, 2005, δ18O and δ13C of Permian brachiopods; a record of seawater evolution and continental glaciation: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 224, p. 333-351. Mii, H.S., E.L. Grossman, T.E. Yancey, B. Chuvashov, and A. Egorov, 2001, Isotopic records of brachiopod shells from the Russian platform; evidence for the onset of mid-Carboniferous glaciation: Chemical Geology, v. 175/1-2, p. 133-147. Popp, B.N., E.A. Laws, R.R. Bidigare, J.E. Dore, K.L. Hanson, and S.G. Wakeham, 1998, Effect of Phytoplankton cell geometry on carbon isotopic fractionation: Geochimica et Cosmochimica Acta, v. 62/1, p. 69-77. Saltzman, M.R., 2003, Late Paleozoic ice age; oceanic gateway or pCO2?: Geology, v. 31/2, p.151-154. Veizer, J., et al., 1999, 87Sr/86Sr, δ13C and δ18O evolution of Phanerozoic seawater: Chemical Geology, v. 161/1-3, p. 59-88.
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